Trace Methods

TypeScript

Laminar.setTraceSessionId(sessionId)

Group this trace with others in a session.

Parameters:

Name	Type	Description
sessionId	string	Session identifier to attach to the trace

Returns: void

Option A: Call inside an active span context

import { Laminar, observe } from '@lmnr-ai/lmnr';

await observe({ name: 'handle_message' }, async () => {
  Laminar.setTraceSessionId('conversation-abc-123');
});

Option B: Pass via observe options

import { observe } from '@lmnr-ai/lmnr';

await observe(
  { name: 'handle_message', sessionId: 'conversation-abc-123' },
  async () => {
    // ...
  },
);

Notes:

• Must run within an active span context to attach to the current trace.
• Prefer setting the session ID at your request/turn entry point so child spans inherit it.

---

Laminar.setTraceUserId(userId)

Associate trace with a user.

Parameters:

Name	Type	Description
userId	string	User identifier to attach to the trace

Returns: void

Option A: Call inside an active span context

import { Laminar, observe } from '@lmnr-ai/lmnr';

await observe({ name: 'handle_request' }, async () => {
  Laminar.setTraceUserId('user-456');
});

Option B: Pass via observe options

import { observe } from '@lmnr-ai/lmnr';

await observe(
  { name: 'handle_request', userId: 'user-456' },
  async () => {
    // ...
  },
);

Notes:

• Must run within an active span context to attach to the current trace.
• Prefer pseudonymous IDs (avoid emails, names, phone numbers).

---

Laminar.setTraceMetadata(metadata)

Add key-value metadata to the trace.

Parameters:

Name	Type	Description
metadata	Record<string, any>	JSON-serializable key-value pairs

Returns: void

Option A: Call inside an active span context

import { Laminar, observe } from '@lmnr-ai/lmnr';

await observe({ name: 'handle_request' }, async () => {
  Laminar.setTraceMetadata({
    environment: 'production',
    region: 'us-west',
    feature_flag: 'new-model-v2',
  });
});

Option B: Pass via observe options

import { observe } from '@lmnr-ai/lmnr';

await observe(
  {
    name: 'handle_request',
    metadata: { environment: 'production', region: 'us-west' },
  },
  async () => {
    // ...
  },
);

Notes:

• Must run within an active span context to attach to the current trace.
• A later call overwrites previous trace metadata—set all keys in one call.
• Values must be JSON-serializable (non-primitive values are JSON-stringified). Stored under lmnr.association.properties.metadata.*.

Overwrite semantics examples

import { Laminar, observe } from '@lmnr-ai/lmnr';

// ✅ Good: set all keys in one call
await observe({ name: 'myFunction' }, async () => {
  Laminar.setTraceMetadata({ environment: 'production', region: 'us-west' });
});

import { Laminar, observe } from '@lmnr-ai/lmnr';

// ❌ Avoid: second call overwrites the first
await observe({ name: 'myFunction' }, async () => {
  Laminar.setTraceMetadata({ environment: 'production' });
  Laminar.setTraceMetadata({ region: 'us-west' });
});

---

Laminar.getTraceId()

Get the current trace ID.

Returns: string | null — UUID string or null if no active span.

import { Laminar, observe } from '@lmnr-ai/lmnr';

await observe({ name: 'operation' }, async () => {
  const traceId = Laminar.getTraceId();
  console.log('Trace:', traceId);
  return { traceId, result };
});

Python

Laminar.set_trace_session_id(session_id=None)

Group this trace with others in a session.

Parameters:

Name	Type	Default	Description
session_id	str | None	None	Session identifier to attach to the trace

Returns: None

Option A: Call inside an active span context

from lmnr import Laminar, observe

@observe()
def handle_message():
    Laminar.set_trace_session_id("conversation-abc-123")

Option B: Pass via @observe(...)

from lmnr import observe

@observe(session_id="conversation-abc-123")
def handle_message():
    # ...
    pass

Notes:

• Warns if called outside span context.
• For dynamic session IDs, set session_id inside the function body.

---

Laminar.set_trace_user_id(user_id=None)

Associate trace with a user.

Parameters:

Name	Type	Default	Description
user_id	str | None	None	User identifier to attach to the trace

Returns: None

Option A: Call inside an active span context

from lmnr import Laminar, observe

@observe()
def handle_request():
    Laminar.set_trace_user_id("user-456")

Option B: Pass via @observe(...)

from lmnr import observe

@observe(user_id="user-456")
def handle_request():
    # ...
    pass

Notes:

• Warns if called outside span context.
• Prefer pseudonymous IDs (avoid emails, names, phone numbers).

---

Laminar.set_trace_metadata(metadata)

Add key-value metadata to the trace.

Option A: Call inside an active span context

from lmnr import Laminar, observe

@observe()
def handle_request():
    Laminar.set_trace_metadata({
        "environment": "production",
        "region": "us-west",
        "feature_flag": "new-model-v2",
    })

Option B: Pass via @observe(...)

from lmnr import observe

@observe(metadata={"environment": "production", "region": "us-west"})
def handle_request():
    # ...
    pass

Parameters:

Name	Type	Description
metadata	dict[str, AttributeValue]	Key-value pairs. Non-primitive values JSON-serialized.

Returns: None

Notes:

• Calling again overwrites previous metadata. Set all keys in one call.
• Warns if called outside span context.

Overwrite semantics examples

from lmnr import Laminar, observe

# ✅ Good: set all keys in one call
@observe()
def my_function():
    Laminar.set_trace_metadata({"environment": "production", "region": "us-west"})

from lmnr import Laminar, observe

# ❌ Avoid: second call overwrites the first
@observe()
def my_function():
    Laminar.set_trace_metadata({"environment": "production"})
    Laminar.set_trace_metadata({"region": "us-west"})

---

Laminar.get_trace_id()

Get the current trace ID.

Returns: uuid.UUID | None — Returns None if called outside span context or invalid trace.

from lmnr import Laminar, observe

@observe()
def operation():
    trace_id = Laminar.get_trace_id()
    return {"trace_id": trace_id, "result": result}